theres no need to change any settings, if you can already join other hosts.
ar you or friend on dial up or dsl? dial up could be the problem,
other then that i cant see why you shouldnt beable to host for 2.
select a place in closed mission add you rnumber of players 2 save info,click the little blue button then open your mission from your mission files once lockon has loaded, easy as that once youve selected your coalition an your plane fly time:), should be a suss.
if ya still struggling just ask one of the guys or galls :S in hyper lobby they should tell ya how.
hope this helps ya out bro
S!